Infix reader-macro by Mark Kantrowitz.

2005-06-06:
* infix.cl: bind *read-suppress* in infix-reader to support the
use of infix notation when *read-suppress* is true.
Christophe Rhodes <csr21@cam.ac.uk>
2002-03-04:
* infix.cl: moved definition of infix-error macro to before its
first use.
Christophe Rhodes <csr21@cam.ac.uk>.